Device and method for producing three-dimensional workpieces

ABSTRACT

The invention relates to a device (1) for producing three-dimensional workpieces (15), comprising a carrier (7) for receiving raw material powder (9), a build chamber wall (11, 11a, 11b) which extend substantially vertically and which is adapted to laterally delimit and support the raw material powder (9) applied to the carrier (7); an irradiation unit (17) for selectively irradiating the raw material powder (9) applied to the carrier (7) with electromagnetic radiation or particle radiation in order to produce on the carrier (7) a workpiece (15) manufactured from the raw material powder (9) by an additive layer building method, wherein the irradiation unit (17) comprises at least one optical element; and a vertical movement device (31) which is adapted to move the irradiation unit (17) vertically relative to the carrier (7). The build chamber wall (11, 11a, 11b) and the carrier (7) are adapted to be connected to one another in a stationary manner during the vertical movement of the irradiation unit (17) so that the vertical movement takes place relative to the carrier (7) and relative to the build chamber wall (11, 11a, 11b).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending U.S. application Ser. No.17/575,822 filed on Jan. 14, 2022, which is a continuation of pendingU.S. application Ser. No. 16/495,958 filed on Sep. 20, 2019, now U.S.Pat. No. 11,247,390, which is the U.S. national phase of internationalapplication PCT/EP2018/055770, filed on Mar. 8, 2018, which claims thebenefit of German application DE 10 2017 205 027.6 filed on Mar. 24,2017; all of which are hereby incorporated herein in their entirety byreference.

BACKGROUND AND SUMMARY

The invention relates to a device and a method for producingthree-dimensional workpieces. In particular, the invention relates to adevice and a method for producing three-dimensional workpieces by meansof an additive layer building method.

In additive methods for the manufacture of three-dimensional workpieces,and in particular in additive layer building methods, it is known toapply an initially shapeless or shape-neutral molding compound (forexample a raw material powder) to a carrier layer by layer and tosolidify it by location-specific irradiation (e.g. by fusion orsintering) in order ultimately to obtain a workpiece of a desired shape.Irradiation can take place by means of electromagnetic radiation, forexample in the form of laser radiation. In a starting state, the moldingcompound can initially be in the form of granules, powder or liquidmolding compound and can be selectively or, in other words,location-specifically solidified as a result of the irradiation. Themolding compound can comprise, for example, ceramics, metal or plasticsmaterials and also material mixtures thereof. A variant of additivelayer building methods relates to so-called powder bed fusion, in whichin particular metallic and/or ceramics raw material powder materials aresolidified to form three-dimensional workpieces.

In order to produce individual workpiece layers it is further known toapply raw material powder material in the form of a raw material powderlayer to a carrier and to irradiate it selectively and in accordancewith the geometry of the workpiece layer that is currently to beproduced. The laser radiation penetrates the raw material powdermaterial and solidifies it, for example as a result of heating, whichcauses fusion or sintering. Once a 5 workpiece layer has solidified, anew layer of unprocessed raw material powder material is applied to theworkpiece layer which has already been produced. Known coaterarrangements or powder application devices can be used for this purpose.Irradiation is then again carried out on the raw material powder layerwhich is now uppermost and is as yet unprocessed. Consequently, theworkpiece is gradually built up layer by layer, each layer defining across-sectional area and/or a contour of the workpiece. It is furtherknown in this connection to use CAD or comparable workpiece data inorder to manufacture the workpieces substantially automatically.

An irradiation unit, or an irradiation system, which can be used, forexample, in a device for producing three-dimensional workpieces byirradiation of raw material powder materials is described in EP 2 333848 B1, The irradiation system comprises a radiation source, inparticular a laser source, and an optical unit. The optical unit, toWhich a processing beam emitted by the radiation source is provided,comprises a beam widening unit and a deflection device in the firm of ascanner unit. Within the scanner unit, diffractive optical elements areprovided in front of a deflection mirror, wherein the diffractiveoptical elements are movable into the beam path in order to split theprocessing beam into a plurality of processing sub-beams. The deflectionmirror then serves to deflect the processing sub-beams.

It will be appreciated that all the aspects discussed above can likewisebe provided within the scope of the present invention.

Known devices for producing three-dimensional workpieces are to befound, for example, in EP 2 961 549 A1 and in EP 2 878 402 A1.

The devices described in those documents each comprise a carrier, whichcan be lowered downwards layer by layer in the vertical direction. Acorresponding vertical movement of the carrier takes place in theseknown devices whenever a layer of the raw material powder has beenirradiated completely and before the next powder layer is applied. Itcan thus be ensured that a focal plane of the irradiation unit is alwayslocated in the layer of the raw material powder that is to be solidified(i.e. in the uppermost layer).

In the known devices described above, the vertical movability of thecarrier requires actuating elements or a lifting mechanism. The liftingmechanism must carry and move inter alia both the workpiece to be builtup and the surrounding powder material. Depending on the size of theinstallation and the size of a corresponding build space, the liftingmechanism used may thereby reach its load limits, which would require amore complex and thus more expensive lifting mechanism. Furthermore, theweight to be moved by the lifting mechanism changes during the buildprocess. This can have the result that the adjustment travel cannot bekept constant between two adjustment operations of the liftingmechanism, which results in undesirable deviations in the layerthickness of the raw material powder layers.

Accordingly, the object of the invention is to provide a solution for anadditive layer building method which reduces or overcomes theabove-mentioned problems and other associated problems, wherein thesolution provides a simple and accurate possibility for controlling thelayer thickness of a raw material powder layer, for example, even in thecase of large build spaces.

The object is achieved by a device having the features of patent claim 1and by a method having the features of patent claim 14.

Accordingly, the invention relates, according to a first aspect, to adevice for producing three-dimensional workpieces. The device comprisesa carrier for receiving raw material powder and a build chamber wallwhich extends substantially vertically and which is adapted to laterallydelimit and support the raw material powder applied to the carrier. Thedevice further comprises an irradiation unit for selectively irradiatingthe raw material powder applied to the carrier with electromagneticradiation or particle radiation, in order to produce on the carrier aworkpiece manufactured from the raw material powder by an additive layerbuilding method, wherein the irradiation unit comprises at least oneoptical element. The device further comprises a vertical movement devicewhich is adapted to move the irradiation unit vertically with respect tothe carrier, wherein the build chamber wall and the carrier are adaptedto be connected to one another in a stationary manner during thevertical movement of the irradiation unit, so that the vertical movementtakes place relative to the carrier and relative to the build chamberwall.

The carrier can thereby provide a horizontal surface to which the rawmaterial powder can be applied layer by layer, that is to say inhorizontal layers. The build chamber wall can thereby serve to laterallydelimit the build chamber. The build chamber can have, forexample—defined by the build chamber wall—a round, elliptical, polygonalor rectangular, in particular a square, cross-section. The raw materialpowder can be so delimited and supported by the build chamber wall thatit is held in shape by the build chamber wall so that it does nottrickle downwards at the sides.

In the present disclosure, the term build chamber is to be understood asmeaning a spatial region in which the application of the raw materialpowder layers takes place and which is delimited at the bottom by thecarrier and at the sides by the build chamber wall. The build chambercan represent a volume which is closed in an air-tight manner and whichis closed in an air-tight manner at the top by a suitable cover regionand optionally by corresponding sealing means. The cover region can bevertically movable together with the irradiation unit. However, thebuild chamber can also be open at the top and thus not define a clearlydefined volume. For example, the build chamber can have the form of acube that is open at the top. The build chamber can be located inside anouter housing and/or inside an outer wall of the device. Furthermore, inaddition to the build chamber, further build chambers can be locatedinside the outer housing as part of the device.

The build chambers described herein can be build chambers having a sidelength of, for example, in each case more than 50 cm. In other words, atleast one of the two orthogonal side lengths of the carrier can be atleast 50 cm. Furthermore, at least one of the two orthogonal sidelengths of the carrier can be at least 100 cm. The carriers used hereincan thus be, for example, carriers having a base area of 1 m×1 m.

The optical element of the irradiation unit can be, for example, a scanunit, a focusing unit and/or an F-theta lens. The irradiation unit canfurther comprise a radiation source, such as, for example, an electronbeam source or a laser. However, the radiation emitted by theirradiation unit can also be supplied to the irradiation unit from aradiation source that is located outside the irradiation unit. Mirrors,optical fibers and/or other light guides, for example, can be used forthis purpose.

The carrier can be connected in a stationary manner to a base of thedevice. The base of the device can comprise, for example, a baseplate ofthe device. The base can be adapted to be immovable after constructionof the device and/or during operation of the device (i.e. during a buildprocess). In particular, the base can be immovable with respect to avertical direction. The term “immovable” here means immovability inrelation to the surroundings in which the device is constructed.

The vertical movement device can comprise a lifting device, for example.The vertical movement device can comprise one or more hydraulic and/ormechanical actuators, During the vertical movement, the irradiation unitcan move up and down independently of the build chamber wall. Inparticular, the build chamber wall can be so configured that it is notmechanically coupled with the irradiation unit and in particular doesnot move up and down together with the irradiation unit.

By means of this immovability of the build chamber wall it can beensured that the raw material powder located therein is not mechanicallyinfluenced during the vertical movement and in particular that there isno undesired disturbance of the raw material powder in edge regions ofthe build chamber, it can thus be ensured that a surface of the rawmaterial powder has the same (largely horizontal and flat) structurebefore and after the vertical movement of the irradiation unit.Furthermore, mechanical friction losses and thus energy losses at thebuild chamber wall/raw material powder interface can be avoided if thebuild chamber wall is not moved relative to the raw material powderduring a build process.

The build chamber wall can be adapted to laterally surround the rawmaterial powder applied to the carrier completely and to delimit andsupport the raw material powder on all sides.

“On all sides” here means that the build chamber wall represents abarrier for the raw material powder in all horizontal directions.However, at least one closable opening can be provided in the buildchamber wall, through which opening raw material powder and/or thefinished workpiece, for example, can be removed.

The build chamber wall can be rigidly connected to the carrier and/or toa base of the device. Alternatively, the build chamber wall can bedetachably connected to the carrier and/or to the base and adapted to bedetached from the carrier on completion of a build process, in order toremove the finished workpiece.

If the build chamber wall is detachably connected to the carrier, itcan, for example, be capable of being lifted upwards in order, oncompletion of a build process, to free the finished workpiece and makeit accessible from the sides. A corresponding lifting device for liftingthe build chamber wall can be provided for this purpose.

The device can further comprise a powder application device which isadapted to apply the raw material powder layer by layer to the carrier.

The powder application device can comprise a powder container or and/orbe connected to a powder reservoir so that raw material powder can besupplied to the powder application device. The powder application devicecan be adapted to move in the horizontal direction over a previouspowder layer and thereby apply a new powder layer. To that end, thepowder application device can comprise at least a roller, a pusherand/or similar suitable means for applying a raw material powder layer.

The vertical movement device can be adapted to move the irradiation unitvertically together with the powder application device.

The powder application device can thereby be fastened, for example, to aholding device which can be moved up and down together with theirradiation unit. The vertical distance between the irradiation unit andthe powder application device can thus be kept constant. It can therebybe ensured that a new applied raw material powder layer is alwayslocated in a focal plane of the irradiation unit.

The device can comprise a further vertical movement device which ismechanically independent of the vertical movement device and which isadapted to move the powder application device vertically.

The further vertical movement device can be fastened, for example, tothe build chamber wall. The further vertical movement device cancomprise guide elements (for example rails) which are provided on aninner side of the build chamber wall and on which the powder applicationdevice can be moved up and down.

The device can further comprise a control unit which is adapted tocontrol the vertical movement device in such a manner that theirradiation unit is vertically adjustable in terms of its heightrelative to the carrier and relative to the build chamber wall accordingto a desired thickness of a respective raw material powder layer that isto be applied.

The control unit can be a central control unit of the device, whichmonitors and/controls a plurality of process sequences of the device.The control unit can comprise a processor (for example a CPU) and amemory. A program which comprises commands which cause the device tocarry out the process sequence described herein can be stored in thememory. An adjustment travel of the vertical movement device, which istravelled in the context of a movement operation between thesolidification of two layers, can correspond to the thickness of a rawmaterial powder layer.

The device can further comprise at least one gas inlet, which is adaptedto direct a gas into a build chamber defined by the build chamber wall,and at least one gas outlet, which is adapted to draw in the gasintroduced from the gas inlet. The gas inlet and the gas outlet can inparticular be adapted to generate a gas stream flowing substantiallyparallel to the carrier.

The gas can be an inert gas, such as, for example, argon or nitrogen.The gas inlet can comprise an opening which is adapted to allow the gasto flow substantially in a horizontal direction along a surface of theraw material powder layer. Furthermore, a gas outlet for drawing in thegas flowing out of the gas inlet can be provided. The gas outlet can bearranged, for example, substantially at the same height as the gasinlet. Furthermore, the gas outlet can be arranged opposite the gasinlet in the direction of a gas stream generated by the gas inlet. Asubstantially horizontal laminar gas stream along a surface of the rawmaterial powder layer can thus be generated.

The vertical movement device can be adapted to move the irradiation unitvertically together with the gas inlet.

It can thus be ensured that the gas inlet is always at a constant heightabove the uppermost raw material powder layer. The gas inlet can therebybe mechanically rigidly coupled with the irradiation unit. If a gasoutlet is additionally provided, the vertical movement device canfurther be adapted to move the irradiation unit vertically together withthe gas inlet and the gas outlet. The device can comprise a plurality ofirradiation units arranged side by side, each of which comprises atleast one optical element and is adapted to scan an electromagnetic beamor a particle beam over the raw material powder, wherein the verticalmovement device is adapted to move the plurality of irradiation unitstogether vertically with respect to the carrier.

The irradiation units can be fastened to a common frame. Furthermore, anirradiation region within the build space can be defined for each of theirradiation units. The irradiation regions can be defined on a commoncarrier or on a plurality of carriers provided for the respectiveirradiation regions. The irradiation units can be adapted to scan,independently of one another, an electromagnetic beam or a particle beamover their respective irradiation region. Furthermore, each of theirradiation units can comprise a radiation source (for example a laser),but it is also possible to provide a common radiation source, the beamof which is split by at least one beam splitter into sub-beams for therespective irradiation units.

The device can further comprise a horizontal movement device, which isadapted to move the irradiation unit horizontally with respect to thecarrier and with respect to the raw material powder applied to thecarrier.

The horizontal movement device can be adapted to be moved horizontallyin such a manner that regions of the build chamber which were notaccessible to the irradiation unit before the horizontal movement areaccessible to the irradiation unit after the horizontal movement and canbe irradiated. In other words, the horizontal movement device can beadapted to be moved horizontally over the same carrier of the same buildchamber. Furthermore, the horizontal movement device can be adapted tomove the irradiation unit from a first build chamber to a second buildchamber, as described hereinbelow.

The device can comprise a plurality of build chambers arranged side byside, each of which has a build chamber wall, which laterally surroundsthe respective build chamber, and a carrier, wherein the horizontalmovement device is adapted to move the irradiation unit from a firstbuild chamber of the plurality of build chambers to a second buildchamber of the plurality of build chambers.

The horizontal movement device can also be so configured that it movesthe build chamber horizontally relative to the irradiation unit, whereinthe irradiation unit remains stationary with respect to a horizontaldirection. It is thus possible to provide, for example, a conveyor beltfor build chambers, by means of which a plurality of build chambers canbe supplied to the irradiation unit by a horizontal movement.

The horizontal movement can be carried out in such a manner that theirradiation unit is first located substantially centrally above thecarrier of the first build chamber and, after the horizontal movement,is located substantially centrally above the carrier of the second buildchamber. The horizontal movement device can have rollers or wheels bymeans of which it can be moved over a common base, wherein the rollersor wheels run over the common base. In addition or alternatively, railsor other suitable guide elements can be provided on the common base inorder to guide the horizontal movement from the first build chamber tothe second build chamber. The carrier of the first build chamber and thecarrier of the second build chamber can be arranged on the common base.Furthermore, the carrier of the first build chamber and/or the carrierof the second build chamber can represent a portion of a surface of thecommon base.

This is the case in principle for all the carriers described herein: Thecarrier can represent a portion of a surface of a larger element, forexample of a base. The carrier—apart from the build chamber wall—doesnot have to be distinguished structurally from a surface surrounding thecarrier. For example, the carrier can be defined merely as an area of abase, wherein the build chamber wall delimits that area at the sides.The build chamber wall can, for example, be capable of being liftedupwards.

The horizontal movement device can also be so configured that theirradiation unit is fastened in a suspended manner to a common cover ofthe device and is guided along that common cover from the first buildchamber to the second build chamber. Rails or other linear or non-linearguide elements, for example, can be provided for that purpose.

The device can further comprise a control unit which is adapted tocontrol the horizontal movement device in such a manner that theirradiation unit, on completion of a first build process in the firstbuild chamber, is moved horizontally to the second build chamber, andthen to control the irradiation unit in such a manner that it begins anew build process in the second build chamber.

The finished workpiece can thus cool down in the first build chamberand/or already be unpacked (freed of excess raw material powder) while abuild process is taking place in the second build chamber. The controlunit can be the same control unit which also controls the verticalmovement device. Alternatively, separate control units can also beprovided. The control unit can further be a central control unit of thedevice. A common control unit of the vertical movement device and thehorizontal movement device can be adapted, for example, on completion ofthe first build process, if required, to lift the irradiation unitvertically completely out of the build chamber, then to move ithorizontally over the build chamber walls of the first and second buildchamber, and to lower the irradiation unit in the second build chamberso that a first raw material powder layer can be applied in the secondbuild chamber and selectively irradiated.

According to a second aspect, the invention relates to a method forproducing three-dimensional workpieces. The method comprises applyingraw material powder to a carrier, wherein the raw material powderapplied to the carrier is laterally delimited and supported by a buildchamber wall extending substantially vertically, and selectivelyirradiating the raw material powder applied to the carrier withelectromagnetic radiation or particle radiation by an irradiation unitin order to produce on the carrier a workpiece manufactured from the rawmaterial powder by an additive layer building method, wherein theirradiation unit comprises at least one optical element. The methodfurther comprises moving the irradiation unit vertically with respect tothe carrier by means of a vertical movement device, while the buildchamber wall and the carrier are connected to one another in astationary manner, so that the vertical movement takes place relative tothe carrier and relative to the build chamber wall.

The method can be carried out, for example, by means of one of thedevices described herein. Furthermore, the method can comprise all themethod steps for which the devices described herein are suitable oradapted.

The method can further comprise moving the irradiation unit horizontallyfrom a first build chamber to a second build chamber by means of ahorizontal movement device, on completion of a build process in thefirst build chamber, and beginning a build process in the second buildchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained hereinbelow with reference to theaccompanying figures, in which:

FIG. 1 : is a schematic side view of a first exemplary embodiment of adevice according to the invention which carries out a method accordingto the invention;

FIG. 2 : is a schematic side view of a second exemplary embodiment of adevice according to the invention which carries out a method accordingto the invention; and

FIG. 3 : is a schematic plan view of a third exemplary embodiment of adevice according to the invention which carries out a method accordingto the Invention.

DETAILED DESCRIPTION OF EMBODIMENTS

In FIG. 1 , a first exemplary embodiment of a device 1 according to theinvention is shown in a schematic side view. The views of the figuresare not necessarily true to scale. A vertical direction (alsoz-direction hereinbelow) is defined in the figure by the arrow 3, and ahorizontal plane (also x-y plane hereinbelow) extends perpendicular tothe plane of the drawing along the base 5.

The base 5 represents a baseplate of the device 1, The device 1 canfurther have an outer housing (not shown) with outside walls and anoutside cover. The device 1 can, however, also be provided without itsown outer housing in an open construction, for example in a factorybuilding.

On the base 5 there is provided a carrier 7 which has a horizontalrectangular surface. The carrier 7 is connected in a stationary mannerto the base 5 and is adapted to receive a plurality of layers of rawmaterial powder 9. Adjacent to the carrier 7 at the sides is a buildchamber wall 11, which surrounds the carrier 7 completely at the sides.Both the carrier 7 and the build chamber wall 11 thus have a rectangularcross-section, when seen in a plan view. The build chamber wall 11laterally surrounds the carrier 7 in such a manner that it is adjacentto the raw material powder 9 located on the carrier 7, supports it atthe sides and holds it in a cuboid shape.

The build chamber wall 11 defines a build chamber 13 located within thebuild chamber wall 11. In the build chamber 13, a process of building aworkpiece 15 by means of an additive layer building method takes place.The build chamber 13 is delimited at the sides by the build chamber wall11 and at the bottom by the carrier 7. A physical delimitation of thebuild chamber 13 at the top is not necessary, in particular the buildchamber 13 does not have to be closed at the top in an air-tight manner.In the representation of FIG. 1 , the build chamber 13 is delimited atthe top by an irradiation unit 17 and by a portion of an irradiationunit carrier 19.

The build chamber 13 can, however, be closed in an air-tight manner, forexample by providing sealing means (not shown) between the build chamberwall 11 and the irradiation unit carrier 19. This has the advantage thata protecting gas (for example an inert gas such as argon or nitrogen)cannot flow out of the build chamber 13, and that impurities cannotenter the build chamber 13, However, air-tight sealing is not absolutelynecessary, for example, in the case of the use of argon as protectinggas, since argon, because of its high density, accumulates in the regionof the build chamber bottom (that is to say in the region of the rawmaterial powder 9) and cannot escape upwards.

The device 1 further has a powder application device 21, by means ofwhich the raw material powder 9 can be applied layer by layer to thecarrier 7, To that end, the powder application device 21 can comprise atleast one roller, at least one pusher and/or other suitable powderapplication means, which are suitable for applying to the carrier 7, orto a previous raw material layer, a raw material powder layer that is asuniformly thick as possible. The powder application device 21 isconnected to a raw material powder reservoir (not shown), in order to besupplied with raw material powder from the reservoir.

The device 1 further has an irradiation unit 17 for selectivelyirradiating the raw material powder 9 applied layer by layer to thecarrier 7. By means of the irradiation unit 17, the raw material powder9 can be exposed to location-specific radiation, in dependence on thedesired geometry of the workpiece 15 to be produced. To that end, theirradiation unit 17 has a radiation source, which can be provided in theform of a laser. The laser can, for example, emit light at a wavelengthof approximately 1064 inn. Alternatively, the radiation source (forexample a laser) can also be located outside the irradiation unit 17 anda beam to be directed onto the raw material powder 9 is fed to theirradiation unit 17, for example, by means of an optical fiber.

The irradiation unit 17 further has optical elements, such as, forexample, a scan unit, a focusing unit and an F-theta lens. The scan unitis adapted to scan the beam over the uppermost raw material powder layerwithin a horizontal plane (in the x-direction and y-direction). Thefocusing unit is adapted to change or adapt a focus position of the beam(in the z-direction), so that a focal plane of the irradiation unit 17is located in the region of the uppermost raw material powder layer,which is irradiated by the irradiation unit 17. The irradiation unit 17can be, for example, an irradiation unit or irradiation device asdescribed in EP 2 333 848 B1.

The device 1 further has a gas inlet 23 and a gas outlet 25, The gasinlet 23 has an opening for the outflow of a gas (for example an inertgas such as argon or nitrogen). The gas outlet 25 further has an openingfor drawing in the gas flowing out of the gas inlet 23. The opening ofthe gas inlet 23 and the opening of the gas outlet 25 are arrangedsubstantially at the same height and at a small distance from a surfaceof the raw material powder 9. In this manner, a laminar andsubstantially horizontal gas stream can be provided parallel to thecarrier 7 over the surface of the raw material powder 9. This gas streamcan be suitable to be able to draw off in a controlled mannerprocess-related impurities (for example splashes and melt deposits), Thegas inlet 23 and the gas outlet 25 can be configured, for example, asdescribed in European patent application 15 186 889.0.

Both the gas inlet 23 and the gas outlet 25 are optional elements of thedevice 1, Wherein those elements can be omitted or provided at adifferent location than that described herein.

The irradiation unit 17, the gas inlet 23 and the gas outlet 25 arefastened to the irradiation unit carrier 19 in such a manner that avertical movement of the irradiation unit carrier 19 leads to a verticalmovement of the irradiation unit 17, the gas inlet 23 and the gas outlet25. Furthermore, the powder application device 21 is fastened to theirradiation unit carrier 19 in such a manner that a vertical movement ofthe irradiation unit carrier 19 leads to a vertical movement of thepowder application device 21. Alternatively, however, the powderapplication device 21 can also be arranged independently of theirradiation unit carrier 19. The powder application device 21 can, forexample, be arranged on the build chamber wall 11 and be provided with acorresponding vertical movement device in order to be moved up and downalong the build chamber wall 11. Furthermore, a horizontal movementdevice is provided for the powder application device 21, by means ofwhich horizontal movement device the powder application device 21 can bemoved over the carrier 7 in the horizontal direction, as is indicated bythe arrow 27. Alternatively or in addition to the movement in thedirection of the arrow 27 (x-direction), the horizontal movement deviceof the powder application device 21 can also be adapted to move thepowder application device 21 in the y-direction over the carrier 7.

The irradiation unit carrier 19 is fastened to a frame 29 in such amanner that it is movable vertically. The irradiation unit carrier 19and thus the irradiation unit 17 can be moved up and down with respectto the frame 29 by means of a vertical movement device 31. The verticalmovement device 31 of the device 1 shown in FIG. 1 comprises a motor,which can be, for example, a step motor or servomotor. The verticalmovement device 31 can be configured in many different ways and cancomprise, for example, any type of actuating elements or lifting device.For example, the vertical movement device 31 can have a hydraulic and/ormechanical actuator. The vertical movement device 31 can have, forexample, a spindle shaft and a motor that drives the spindle shaft.

By means of the vertical movement device 31, a vertical distance betweenthe irradiation unit 17 and the carrier 7 can be changed. In particular,that distance can be so changed that a distance between the irradiationunit 17 and the uppermost layer of the raw material powder 9 alwaysremains constant. The vertical movement of the vertical movement device31 takes place independently of and relative to the build chamber wall11, that is to say in particular that the build chamber wall 11 is notmoved by the vertical movement device 31.

The device 1 further comprises a control unit 33 which is adapted tocontrol the vertical movement device 31 and a horizontal movement device35 described hereinbelow. The control unit 33 comprises a CPU and amemory, wherein a program is stored in the memory, which program, whenexecuted by the CPU, causes the device 1 to carry out one of the methodsdescribed herein. The control unit 33 can further take over all thecontrol tasks of the device 1 and, for example, control the irradiationunit 17, the powder application device 21, the gas stream through thegas inlet 23 and the gas outlet 25.

A build process of the device 1 takes place in such a manner and iscontrolled by the control unit 33 in such a manner that the verticalmovement device 31 moves the powder application device 21 downwards tosuch an extent that the powder application device 21 can apply a firstraw material powder layer to the carrier 7. Then or at the same time,the vertical movement device 31—if necessary—moves the irradiation unit17 to a height which is suitable for selectively irradiating that firstraw material powder layer and solidifying it (for example by fusion orsintering). The scan unit thereby scans the beam over the raw materialpowder 9 in accordance with a predetermined pattern. Once the first rawmaterial powder layer has been irradiated as desired, the verticalmovement device 31 moves the powder application device 21 to a height atwhich it can apply a second raw material powder layer to the first rawmaterial powder layer. An operation of irradiating the second rawmaterial powder layer then takes place, analogously to the irradiationof the first raw material powder layer.

During the building of the desired workpiece 15, the vertical movementdevice 31 thus moves the irradiation unit 17 (and where applicable thefurther components fastened to the irradiation unit carrier 19, namelythe gas inlet 23, the gas outlet 25 and/or the powder application device21) increasingly further away from the carrier 7. The irradiation unit17 can then be lifted upwards out of the build chamber 13 completely andmoved by means of a horizontal movement device 35 to a further buildchamber, as will be described hereinbelow with reference to FIG. 3 .

Once the build process in the build chamber 13 is complete, the finishedworkpiece 15 can cool down, and then a lifting device (not shown) canlift the build chamber wall 11 upwards so that excess raw materialpowder 9 is able to trickle out of the build chamber 13 at the sides andthe finished workpiece 15 is accessible from the sides. The workpiece 15can then be freed from the excess raw material powder 9 completely.Furthermore, a closable opening can be provided in the build chamberwall 11, which opening can be opened after the build process and throughwhich the finished workpiece 15 and/or excess raw material powder 9 canbe removed.

The frame 29 of the device 1 further has a horizontal movement device35. In the exemplary embodiment of FIG. 1 , the horizontal movementdevice 35 comprises rollers by means of which the frame 29 together withthe irradiation unit carrier 19 fastened thereto and the components(irradiation unit 17, gas inlet 23, gas outlet 25 and/or powderapplication device 21) fastened to the irradiation unit carrier 19 canbe moved horizontally. The rollers are driven by one or more motors,wherein the motors are controlled by the control unit 33. The frame 29is thereby rolled over the base 5 by means of the rollers. In addition,it is possible to provide corresponding (linear or non-linear) guideelements such as, for example, rails, which guide the horizontalmovement of the frame 29 over the base 5. Alternatively to the form ofFIG. 1 , in which the frame 29 is rolled over the base 5 via rollers,the frame 29 can be fixed in a horizontally movable manner to a cover ofan outer housing of the device 1, Which can be ensured, for example, bycorresponding rails.

The horizontal movement device 35 can be so configured that it permitsnot only a linear movement in a horizontal direction but also controlledmovements within the horizontal plane (both in the x-direction and inthe y-direction).

The horizontal movement device 35 can on the one hand serve to makeregions of the raw material powder layers which were not accessible tothe irradiation unit 17 before the horizontal movement accessible to theirradiation unit 17 during the process of building the workpiece 15, Aneffective build area can thus be enlarged, and larger workpieces 15 canbe produced. On the other hand, the horizontal movement device 35 canserve to move the irradiation unit 17 from a first build chamber to asecond build chamber, as will be described below with reference to FIG.3 .

In FIG. 2 , a second exemplary embodiment of a device 1 according to theinvention is shown in a schematic side view. Elements having the samereference numeral correspond to those of the device 1 of FIG. 1 . Themode of operation of those elements is identical to the mode ofoperation of the corresponding elements of the device 1 of FIG. 1 .

In a departure from the device 1 of FIG. 1 , the device 1 of FIG. 2 hasnot only one but a plurality of irradiation units 17 arranged side byside. In the example of FIG. 2 , three irradiation units 17 areprovided, wherein it is also possible to provide fewer or moreirradiation units 17. Each of the irradiation units 17 defines anirradiation region on a common carrier 7. In each of the irradiationregions, a workpiece 15 can be produced. It is, however, also possiblethat the irradiation regions of the irradiation units 17 are directlyadjacent to one another or overlap, so that a large workpiece can beproduced, wherein each of the irradiation units 17 is responsible forsolidifying a predetermined region of the workpiece. The threeirradiation regions are located in a common build chamber 13, which issurrounded by a build chamber wall 11.

For each of the irradiation units 17 there are provided a gas inlet 23and a gas outlet 25 for generating a horizontal gas stream over therespective irradiation region. Alternatively, however, it is alsopossible to provide only a common gas inlet and a common gas outlet 25,so that, for example, a gas inlet 23 and a gas outlet 25 are providedonly in the outer regions of the irradiation unit carrier 19, The device1 further has a common powder application device 21 which is able toapply powder layers over the entire area of the carrier 7.Alternatively, each of the irradiation regions can be provided with itsown powder application device.

Because the device 1 of FIG. 2 has a plurality of irradiation units 17,it is possible on the one hand to produce larger (common) workpieces,and on the other hand it is possible to produce a plurality ofworkpieces 15 simultaneously, which leads to a reduced process time perworkpiece 15.

FIG. 3 shows a third exemplary embodiment of a device 1 for producing athree-dimensional workpiece, wherein the device 1 of the third exemplaryembodiment can comprise, for example, the device 1 of FIG. 1 or thedevice 1 of FIG. 2 . The device 1 of FIG. 3 comprises a first buildchamber 13 a and a second build chamber 13 b. Further build chambers(not shown) can also be provided.

In FIG. 3 , the first build chamber 13 a and the second build chamber 13b are shown in a plan view. The build chamber 13 a is surrounded by abuild chamber wall 11 a, and the build chamber 13 b is surrounded by abuild chamber wall 11 b. The build chamber 13 a or 13 b can be, forexample, one of the build chambers 13 shown in FIG. 1 or FIG. 2 . Thebuild chambers 13 a and 13 b are arranged on a common base 5.

Furthermore, in the state shown in FIG. 3 , the frame 29 is locatedabove the first build chamber 13 a, so that a workpiece 15 can beproduced inside the build chamber 13 a by an additive layer buildingmethod. The elements of the device 1 that are necessary thereforcorrespond, for example, to those of FIG. 1 or FIG. 2 .

On completion of the build process in the first build chamber 13 a, theframe 29 moves by means of the horizontal movement device 35 over thebase 5 from the first build chamber 13 a to the second build chamber 13b, as shown by the arrow 37. Over the second build chamber 13 b, theirradiation unit 17, or the irradiation units 17, is/are then lowered bymeans of the vertical movement device 31 over the carrier 7, and a new(second) build process is begun in the second build chamber 13 b.

During the second build process, the workpiece 15 in the first buildchamber 13 a can cool down and already be removed, for example, bylifting the build chamber wall 11 a or through an opening in the buildchamber wall 11 a.

This allows a plurality of workpieces 15 to be produced in a pluralityof build chambers 13 a, 13 b by means of a reduced number of irradiationunits 17, compared with a situation in which each of the build chambers13 a, 13 b has its own irradiation unit 17 or own irradiation units 17.In addition to the two build chambers 13 a and 13 b shown in FIG. 3 ,further build chambers with corresponding build chamber walls can beprovided, so that the frame 29 together with its irradiation unit(s) 17(and where appropriate the further components fastened to theirradiation unit carrier 19, namely gas inlet/inlets 23, gasoutlet/outlets 25 and/or powder application device(s) 21) can move tothose build chambers in succession and in each case can carry out abuild process in the respective build chamber.

The build chambers 13, 13 a, 13 b described herein can be large buildchambers with a side length of, for example, in each case more than 50cm. In other words, at least one of the two orthogonal side lengths ofthe carrier 7 can be at least 50 cm. Furthermore, at least one of thetwo orthogonal side lengths of the carrier 7 can be at least 100 cm. Thecarriers 7 used herein can thus be carriers having a base area of 1 m×1m.

Because the device described herein has a vertically movable irradiationunit, a relative movement of the irradiation unit relative to thecarrier takes place without the carrier having to be moved. Whencorrespondingly large carriers are used, this has the advantage that itis not necessary to move a heavy amount of powder and a heavy workpieceduring the build process.

Furthermore, the irradiation unit is moved relative to the build chamberwall, so that the build chamber wall remains stationary with respect tothe raw material powder and no friction takes place at an interfacebetween the build chamber wall and the raw material powder, and thus thepowder layers are not disturbed. Because the build chamber wall remainsstationary with respect to the raw material powder, it is relativelyunproblematic to seal the build chamber wall relative to the carrier,that is to say to ensure that no powder can pass through a gap betweenthe build chamber wall and the carrier. In conventional devices, suchsealing represents a greater problem because the carrier must be able tomove vertically relative to the build chamber wall.

Movability of the irradiation unit independently of the build chamberwall further permits movability of the irradiation unit from a firstbuild chamber to a second build chamber and, from there, optionally tofurther build chambers.

1. A device for producing three-dimensional workpieces, comprising: acarrier for receiving raw material powder, a build chamber wall whichextends substantially vertically and which is adapted to laterallydelimit and support the raw material powder applied to the carrier, anirradiation unit for selectively irradiating the raw material powderapplied to the carrier with electromagnetic radiation or particleradiation in order to produce on the carrier a workpiece manufacturedfrom the raw material powder by an additive layer building method,wherein the irradiation unit comprises at least one optical element, anda vertical movement device which is adapted to move the irradiation unitvertically with respect to the carrier, wherein the build chamber walland the carrier are adapted to be connected to one another in astationary manner during the vertical movement of the irradiation unitso that the vertical movement takes place relative to the carrier andrelative to the build chamber wall, wherein the build chamber wall isrigidly connected to the carrier and to a base of the device, or whereinthe build chamber wall is detachably connected to the carrier and to thebase and is adapted to be detached from the carrier on completion of abuild process, in order to remove the finished workpiece.
 2. The deviceas claimed in claim 1, wherein the build chamber wall is adapted tolaterally surround the raw material powder applied to the carriercompletely and to delimit and support the raw material powder on allsides.
 3. The device as claimed in claim 1, further comprising a powderapplication device which is adapted to apply the raw material powderlayer by layer to the carrier.
 4. The device as claimed in claim 3,wherein the vertical movement device is adapted to move the irradiationunit vertically together with the powder application device.
 5. Thedevice as claimed in claim 3, further comprising a further verticalmovement device which is mechanically independent of the verticalmovement device and which is adapted to move the powder applicationdevice vertically.
 6. The device as claimed in claim 1, furthercomprising a control unit which is adapted to control the verticalmovement device in such a manner that the irradiation unit is verticallyadjustable in terms of its height relative to the carrier and relativeto the build chamber wall according to a desired thickness of arespective raw material powder layer that is to be applied.
 7. Thedevice as claimed in claim 1, further comprising at least one gas inletwhich is adapted to direct a gas into a build chamber defined by thebuild chamber wall, and at least one gas outlet which is adapted to drawin the gas introduced from the gas inlet, wherein the gas inlet and thegas outlet are in particular adapted to generate a gas stream flowingsubstantially parallel to the carrier.
 8. The device as claimed in claim7, wherein the vertical movement device is adapted to move theirradiation unit vertically together with the gas inlet and the gasoutlet.
 9. The device as claimed in claim 1, wherein the devicecomprises a plurality of irradiation units arranged side by side, eachof which comprises at least one optical element and each of which isadapted to scan an electromagnetic beam or a particle beam over the rawmaterial powder, and wherein the vertical movement device is adapted tomove the plurality of irradiation units together vertically with respectto the carrier.
 10. The device as claimed in claim 1, further comprisinga horizontal movement device which is adapted to move the irradiationunit horizontally with respect to the carrier and with respect to theraw material powder applied to the carrier.
 11. The device as claimed inclaim 10, wherein the device comprises a plurality of build chambersarranged side by side, each of Which has a build chamber wall Whichlaterally surrounds the respective build chamber, and a carrier, andwherein the horizontal movement device is adapted to move theirradiation unit from a first build chamber of the plurality of buildchambers to a second build chamber of the plurality of build chambers.12. The device as claimed in claim 11, further comprising a control unitwhich is adapted to control the horizontal movement device in such amanner that the irradiation unit, on completion of a first build processin the first build chamber, is moved horizontally to the second buildchamber, and then to control the irradiation unit in such a manner thatit begins a new build process in the second build chamber.
 13. A methodfor producing three-dimensional workpieces, comprising: applying rawmaterial powder to a carrier, wherein the raw material powder applied tothe carrier is laterally delimited and supported by a build chamber wallextending substantially vertically, selectively irradiating the rawmaterial powder applied to the carrier with electromagnetic radiation orparticle radiation by an irradiation unit in order to produce on thecarrier a workpiece manufactured from the raw material powder by anadditive layer building method, wherein the irradiation unit comprisesat least one optical element, and moving the irradiation unit verticallywith respect to the carrier by means of a vertical movement device,while the build chamber wall and the carrier are connected to oneanother in a stationary manner, so that the vertical movement takesplace relative to the carrier and relative to the build chamber wall,wherein the build chamber wall is rigidly connected to the carrier andto a base, or wherein the build chamber wall is detachably connected tothe carrier and to the base and is detached from the carrier oncompletion of a build process, in order to remove the finishedworkpiece.
 14. The method as claimed in claim 13, further comprising:moving the irradiation unit horizontally from a first build chamber to asecond build chamber by means of a horizontal movement device, oncompletion of a build process in the first build chamber, and beginninga build process in the second build chamber.